The fuse argument is much like the power cord argument. People contend
that inexpensive wire is in your walls, so why would the last 6 feet
matter, and yet most people reading this will agree that it does.
Thom, its not hard to measure the effects of the power cord. The measurements seem to correlate with listening experience (on an amplifier, measure the voltage drop across the cord and also measure the power output; compare to the power output of the amp if the voltage is corrected at the IEC connection using a variac).
We've seen a 2 volt drop across some power cords, which with some of our amplifiers results in a loss of 40 watts. Pretty significant and not a measurement 'buried in the noise'.
You can also measure the effects of a fuse, however we've not been able to measure any effects of the boutique fuses as being any different than the regular ones, assuming that they were indeed the right rating. All that I've ever used is a regular 3 1/2 digit DVM.
If you could use the wiring in the walls as a power cord it would work quite well. However such use is illegal and dangerous due to the wire being solid core.